1. Field of the Invention
The present invention relates to a roaming method and appurtenant devices. The invention relates in particular to a roaming method and appurtenant devices which are based on the GSM specifications and which are a further development of international roaming.
Roaming is understood to mean the operation of a GSM terminal outside the home network. However, the invention may also be utilized for the problem of roaming between different GSM networks and/or non-GSM networks, for example for roaming between networks working according to different standards such as, e.g., GSM, UMTS, intelligent networks (IN), etc.
2. Related Art
By means of so-called xe2x80x9cindirect roaming,xe2x80x9d an operator of a mobile radio network, that is, a mobile operator, can offer his mobile subscribers blanket coverage without having to set up the whole radio network in his licensed territory. In addition, through xe2x80x9cindirect roaming,xe2x80x9d quick access to worldwide roaming is also made possible.
Patent document WO98/10614, the contents of which are incorporated here by reference, describes a method for xe2x80x9cindirect roamingxe2x80x9d which enables a subscriber of a home mobile radio network (Home Public Land Mobile Network, HPLMN) to connect to a visited mobile radio network (Visited Public Land Mobile Network, VPLMN) without a roaming agreement with the home mobile radio network (HPLMN), the connection taking place through means, for example an IMSI number (IMSI=International Mobile Subscriber Identity) and a MSISDN number (MSISDN=Mobile Subscriber Integrated Services Digital Network), which are made available by a partner network (Partner Public Land Mobile Network, PPLMN) having a roaming agreement with the home mobile radio network (HPLMN), on the one hand, and with the visited mobile radio network (VPLMN), on the other hand.
In the method described in WO98/10614, each SIM card (SIM=Subscriber Identity Module) of the subscribers of the HPLMN contains two IMSI numbers. Each IMSI number is assigned a different call number (MSISDN). The first IMSI number belongs to the number range of the home mobile radio network (HPLMN), the second to the number range of the partner network PPLMN. In order to log on to a visited network (VPLMN-NR, NR=No Roaming) which has no roaming agreement with the HPLMN, the subscriber can exchange the first IMSI (of the HPLMN) for the second IMSI (of the PPLMN) and is thereby regarded in the visited network (VPLMN) as a subscriber of the partner network (PPLMN).
Since in the method described in WO98/10614, each IMSI is assigned another, differing MSISDN, calls with the first MSISDN for the subscriber must be diverted by means of an extravagant mechanism, in a so-called UBICOM turntable. Subscriber-specific data, for example call diversions, additional numbers, etc., are, moreover, quite conventionally assigned to the IMSI and are thus available only in the home mobile radio network (HPLMN) or in visited mobile radio networks (VPLMN-WR, WR=with roaming) having a roaming agreement with the HPLMN.
Hence an object of the invention is to offer a method and a system which avoid these drawbacks.
According to the present invention, this goal is achieved especially through the elements of the independent claims. Further advantageous embodiments follow besides from the dependent claims and the description.
In particular, this goal is achieved by the invention in that, in the method according to the invention, which enables a subscriber of a home mobile radio network (Home Public Land Mobile Network, HPLMN) to connect to a visited mobile radio network (Visited Public Land Mobile Network, VPLMN) without a roaming agreement with the home mobile radio network (HPLMN), in that the subscriber receives an identification module having a first mobile subscriber identification (International Mobile Subscriber Identity, IMSI) from the number range of his home mobile radio network (HPLMN) and having a second mobile subscriber identification (IMSI) from the number range of a partner network (Partner Public Land Mobile Network, PPLMN), which partner network (PPLMN) possesses additional roaming agreements, a common call number (Mobile Subscriber Integrated Services Digital Network, MSISDN) is allocated to the two said mobile subscriber identifications (IMSI). The allocation of a common call number (MSISDN) to the different mobile subscriber identifications (IMSI) has the particular advantage that a subscriber can be reached via this one call number (MSISDN) even if he logs on with different mobile subscriber identifications (IMSI) to his home mobile radio network (HPLMN) and to a visited mobile radio network (VPLMN), respectively. The assignment of two (or more) mobile subscriber identifications (IMSI) to a subscriber, one from the number range of the home mobile radio network (HPLMN) and one from the number range of a partner network (PPLMN) has, moreover, the advantage that the subscriber does not depend merely upon the roaming agreements of the operator of the partner network (PPLMN), but that he can additionally profit also by roaming agreements of his home network operator possibly concluded later. As has already been mentioned at the beginning, the invention relates to mobile networks according to the GSM standard; but it may also be utilized in other mobile networks, for instance in UMTS mobile networks (UMTS=Universal Mobile Telephone System), or in particular also for roaming between different GSM and/or non-GSM networks.
In a preferred modification, the identification module activates the second mobile subscriber identification (IMSI) from the number range of a partner network (PPLMN) when it cannot log on to a network with the first mobile subscriber identification (IMSI) from the number range of its home mobile radio network (HPLMN). The activation of an alternate mobile subscriber identification (IMSI) may be initiated in various modifications, which may be implemented as common, situation-dependent modifications or as separate modifications, automatically or by the subscriber, for instance by means of the input means of his terminal.
In various modifications, the first mobile subscriber identification (IMSI)xe2x80x94from the number range of the home mobile radio network (HPLMN)xe2x80x94is (sub-modification a1) filed in the home file (Home Location Register, HLR) of this home mobile radio network, and the second mobile subscriber identification (IMSI)xe2x80x94from the number range of the partner network (PPLMN)xe2x80x94is converted from the first mobile subscriber identification (IMSI), or (sub-modification a2) the first and the second mobile subscriber identification (IMSI) are both filed in the home file (HLR) of the home mobile radio network (HPLMN) and linked to a single call number (MSISDN). Preferably, only one mobile subscriber identification (IMSI) is active at any one time.
Preferably, separate bills are prepared for the respective subscriber for at least certain ones of the at least two mobile subscriber identifications (IMSI) linked to the same call number (MSISDN), whereas a common bill is prepared for the respective subscriber for at least certain others of the at least two mobile subscriber identifications (IMSI) linked to the same call number (MSISDN). This situation-specific billing has the advantage that it is very flexible and that according to the application, and not just in connection with xe2x80x9cindirect roaming,xe2x80x9d separate bills may be prepared for a subscriber for different purposes of use, the mobile subscriber identification (IMSI) corresponding to the purpose and the billing being active in each particular instance, for instance different mobile subscriber identifications (IMSI) for official use and personal use.
The goal of the invention is especially also achieved in that an identification module according to the invention, which is intended for use in a mobile apparatus and makes possible the storage of at least two mobile subscriber identifications (IMSI), contains at least one first mobile subscriber identification (IMSI) from the number range of a home mobile radio network (HPLMN) and a second mobile subscriber identification (IMSI) from the number range of a partner network (PPLMN), the two mobile subscriber identifications (IMSI) being linked to a common call number (MSISDN).
The goal of the invention is especially also achieved in that a programmable device according to the invention having a home file (HLR) in which for every subscriber of a home mobile radio network (HPLMN) contains [sic] at least one mobile subscriber identification (IMSI) and at least one appurtenant call number MSISDN), this home file (HLR) containing for at least certain subscribers a first mobile subscriber identification (IMSI) from the number range of their home mobile radio network (HPLMN), a second mobile subscriber identification (IMSI) from the number range of a partner network (PPLMN), and a call number (MSISDN) assigned to these two mobile subscriber identifications (IMSI) jointly. Preferably in this programmable device, a flag indicates for each subscriber which of the mobile subscriber identifications (IMSI) is active at the moment.